For some reason (beyond my knowledge of hex/ascii conversions stuff!) when a hex code from the extended ASCII table is used (i.e. beyond decimal value 127) NodeJS allocates two bytes for it in the Buffer object. The commands for cashdraw end with \xfa which corresponds to the decimal value 250. This results in two characters (bytes?) and ends up opening the cashdraw but also printing an extra character (usually a space, but I've also seen ||) in the seubsequent print.
As the last part of the cashdraw command is only a time value (ie. 2ms x T2), and T2 can be anywhere between 00 and FF (see Controlling the Cash Drawer in here) I figured if we just use a value less than 127 it should
a) still work, and
b) not cause an extra character in subsequent prints
I picked \x78 which is 120 in decimal, so gives a T2 of 240ms before the next command can be issued.
I've tested this with an ESC/POS receipt printer and nicely fixes the problem.
Maybe this wasn't tested properly at time of develoment but there is an issue with the cashdraw kick commands' hex codes.
See this issue https://github.com/song940/node-escpos/issues/303
For some reason (beyond my knowledge of hex/ascii conversions stuff!) when a hex code from the extended ASCII table is used (i.e. beyond decimal value 127) NodeJS allocates two bytes for it in the
Bufferobject. The commands for cashdraw end with\xfawhich corresponds to the decimal value 250. This results in two characters (bytes?) and ends up opening the cashdraw but also printing an extra character (usually a space, but I've also seen||) in the seubsequent print.As the last part of the cashdraw command is only a time value (ie. 2ms x T2), and T2 can be anywhere between
00andFF(see Controlling the Cash Drawer in here) I figured if we just use a value less than 127 it should a) still work, and b) not cause an extra character in subsequent printsI picked
\x78which is 120 in decimal, so gives a T2 of 240ms before the next command can be issued.I've tested this with an ESC/POS receipt printer and nicely fixes the problem.